1. Field of the Invention
This invention relates generally to a device for collecting bone material during a surgical procedure and, more particularly, to a device for collecting bone material during spinal fusion surgery that includes a filter for separating blood and other liquid matter from the collected material so that the separated bone material can be used as graft material for spinal fusion.
2. Discussion of the Related Art
The human spine includes a series of vertebrae interconnected by connective tissue referred to as disks that act as a cushion between the vertebrae. The disks allow for movement of the vertebrae so that the back can bend and rotate.
Spinal fusion is a surgical procedure that fuses two or more vertebrae together using bone grafts and/or other devices. Spinal fusion is a commonly performed procedure for the treatment of chronic neck and back pain refractory to non-operative treatments. Spinal fusion is used to stabilize or eliminate motion of vertebrae segments that may be unstable, i.e., move in an abnormal way, that may lead to pain and discomfort. Spinal fusion is typically performed to treat injuries to the vertebrae, degeneration of the spinal disks, abnormal spinal curvature and a weak or unstable spine.
Spinal fusion generally requires a graft material, usually bone material, to fuse the vertebrae together. The bone graft material can be placed over the spine to fuse adjacent vertebrae together. Alternatively, a cage is positioned between the vertebrae being fused, and is filed with the graft material. The cage includes holes that allow the vertebrae and the graft material to grow together to provide the fusion. The cage supports the weight of adjacent vertebrae while the fusion is occurring through the cage. Typically the bone graft material is autogenous bone material taken from the patient, or allograft bone material harvested from cadavers. Synthetic bone materials can also be used as the graft material. Generally, the patient's own bone material offers the best fusion material and is the current “gold standard”.
Known bone fusion materials include an iliac crest harvest from the patient, bone graft extenders, such as hydroxyapetite and demineralized bone matrix, and bone morphogenic protein. However, using these materials provides a number of disadvantages. Autologous graft harvest is associated with increased operative and anesthetic time, increased blood loss, increased patient discomfort and increased hospital stay. Iliac crest harvest includes complications and post-operative pain, and is associated with a 15% complication rate. Further, iliac crest harvest can be complicated by wound hematomas and infections, neuropraxias and chronic pain, iliac fractures and bowel injuries. Also, iliac crest graft harvest is painful and makes early ambulation difficult. Bone graft extenders are expensive, are not the patient's own bone, often dissolve and often do not form good bone material when used alone. Some studies have shown complete resolution of these substrates without bone formation despite their touted benefits by industry. Bone morphogenic protein, though shown to be effective at bone formation, is extremely expensive, and can lead to complications, such as soft-tissue swelling, bone formation in places that it should not be, etc. Further, bone morphogenic protein is a poor graft material for posterolateral fusions.
During most spinal surgical procedures, a drill is used to take bone away to allow for decompression of the spinal nerves and/or the spinal cord. Bone is also drilled from the spine to create a “decorticated” fusion bed. Typically, this bone is removed by suction and transported into a large trap outside the surgical field along with the blood and irrigation solution. The collected material is then discarded as surgical waste.